MIT license vs Dynamic Linking

Andrew J Bromage ajb at buzzword.cc.monash.edu.au
Wed Nov 17 00:18:03 UTC 1999


G'day all.

On Tue, Nov 16, 1999 at 12:00:34AM -0800, Bruce Perens wrote:

> Regarding whether or not a GPL copyright owner can make a claim on a derived
> work, sure he can - copyright law provides for that. On a dynamic-link work?
> That depends. Probably if your executable uses headers that are part of the
> work, as they are copied into the executable.

This, of course, only applies to the C/C++ world, where module use is
achieved by textual inclusion of source files (i.e. headers).  In Java,
use of a module is achieved by inspecting the compiled version of the
module.  In other languages, such as Modula-3, when the module to be
used is compiled, the compiler often produces a special interface or
import file which is later inspected by users of the module when they
are compiled.

One could argue that the interface/import file is a derived work of the
original source, but it'd be hard to argue that a special interface or
import file is "copied into the executable" in such languages.  Taking
the example to absurd extremes, as is the custom at this point in any
such example, does what consitiutes a "derived work" now depend on how
the compiler performs its job?  Could it vary from compiler to compiler
for source written in the same language, depending on whether or not 
your compiler uses textual inclusion to implement module importing?

> RMS' law school instructor argues that dynamic linking is a device to
> deliberately circumvent copyright law, and thus should be considered the
> same as static linking. That interpretation could win in court, or not.

Strange, I thought it was a device to control use of system resources. :-)

I guess that interpretation might work if you could prove intent.

Cheers,
Andrew Bromage



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